Does a pdl exist for simple client-server architecture?

[Steve Pringle]

We have an application that we want the interface engine (IE) to connect to and receive data from, but I don’t know if there exists a pdl to handle the requirements, which are:

IE connects to the application via an IP address and a port number.

When the IE opens the IP/port the application (which has been monitoring the port) sends over a stream of data (wrapped in xml). The application then sends data whenever an update occurs in the application.  The IE takes the data and sends it to a SQL Server via a tcl proc (for now – this may change later).

Question is, which pdl to use?  The mlp_tcp.pdl expects to *send* data when it opens an IP/port, not listen and receive data.  I need a pdl that will open an IP/port and just listen for data.

Any help greatly appreciated!

thanks,

Steve Pringle

Topic

[Charlie Bursell]

Huh?

This is a bit confusing to me as to what you want.   Any PDL will open a port for listening (Server).  What you have failed to mention is how the messages are delimited.  Are they encapsulated or do they use a length encoding scheme?  This is what will determine if yoy need a PDL.

FWIW, Cloverleaf 5.6 Rev 1 now includes a delay and disconnect feature for TCP/IP connections.

[Steve Pringle]

Sorry for the confusion.  My understanding is that the application sending the data to the IE sends it as xml; e.g.,

 

 

If I telnet into the IP & port number I get xml as shown above.

Make sense?

Do I even need a pdl?

thanks!

–Steve Pringle

[Charlie Bursell]

If the data is to come via TCP/IP you must have some method to delimit a message, e.g., encapsulation or length encoding.  If the vendor uses one we already recognize no new PDL is needed, else you may need to do something.

[Steve Pringle]

I see.  I know little to nothing about pdls – it sounds like using encapsulation would be the simplest.  The vendor would have to implement it, or I could write a pdl.

If the vendor used encapulation, what is the simplest way to do that given that I want to use an existing pdl?

Is there a document on how to write a pdl?

thanks,

Steve Pringle

[Jim Kosloskey]

Steve,

In my mind the simplest is length encoded and it should be the simplest for the vendor as well.

Frankly, I would be wary of any vendor that has not already incorporated some sort of encapsulation for TCP/IP transmission. It makes me wonder what else they don’t clearly understand.

You could ask them to deploy the HL/7 MLP encapsulation technique, but you need to assure there will not be any ‘binary’ type data in the XML message. If there is, then some portion of the encapsulation set may exist in the actual message and cause issues.

So overall, I would go with length encoded should I have a choice.

Jim Kosloskey

email: jim.kosloskey@jim-kosloskey.com 29+ years Cloverleaf, 59 years IT - old fart.

[Steve Pringle]

Jim,

That’s the conclusion I came to after sleeping on it.

As for the vendor, this is a custom enhancement they’re doing for us and they’ll only be sending text (bed and nurse assignements for a unit), so we should be ok there. But your point on being wary of the vendor’s expertise in this area is well taken.

I’m new to cloverleaf and the healthcare world, so perhaps you could shed some light on the length encoded format the (pdl name here) expects?  A control char, followed by 2 bytes for length, or?

thanks,

Steve

[Jim Kosloskey]

Steve,

In Cloverleaf(R) with length encoding, there is no PDL in use.

Select tcp/ip from the Protocol pull down in the NetConfig and fill in the appropriate information.

If you need a more detailed exchange, email me directly.

Thanks,

Jim Kosloskey

email: jim.kosloskey@jim-kosloskey.com 29+ years Cloverleaf, 59 years IT - old fart.

[Steve Pringle]

Jim,

Let me play around with this – I see where I need to configure the protocol.

Thanks very much!

–Steve

[Author]

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